apply four sprays per arm into the palm and rub onto one limb and repeat for each limb every 4 waking hours.

22% of dropouts related to skin irritation.

VitaminDWiki

Both Magnesium and Vitamin D can be used internally and topically
I use all 4: 1) Vit D internally, 3) Vit D topically,3) Mg internally, 4)Mg topically
I have used transdermal Magnesium Chloride for several years.
Relieves most muscle pain (exercise, back, sprain) in about 10 minutes
It has also has eliminated osteoarthritis pain in my knees
I add Magnesium Chloride oil into a DMSO cream (Amazon $18) for quick penetration
I have tried an assortment of DMSOs and MgCl, and now make my own MgCl oil from MgCl crystals
Usually just a single treatment of about 1/8 teaspoon is needed.
Rarely a second or third treatment is needed the same day to relive muscle pain
Henry Lahore, admin of VitaminDWiki
Note - several friends are now using MgCl to greatly reduce their heart arrhythmias
See also VitaminDWiki

BACKGROUND:
Fibromyalgia is a syndrome characterized by chronic pain, fatigue, depression, and sleep disturbances. Its primary cause is unclear. Several studies have reported decreased intracellular magnesium levels in patients with fibromyalgia and have found negative correlation between magnesium levels and fibromyalgia symptoms.

OBJECTIVE:
To gather preliminary data on whether transdermal magnesium can improve quality of life for women who have fibromyalgia.

DESIGN, SETTING, PARTICIPANTS AND INTERVENTIONS:
This is a patient questionnaires and survey in a fibromyalgia clinic at a tertiary medical center. Forty female patients with the diagnosis of fibromyalgia were enrolled. Each participant was provided a spray bottle containing a transdermal magnesium chloride solution and asked to apply 4 sprays per limb twice daily for 4 weeks. Participants were asked to complete the Revised Fibromyalgia Impact Questionnaire, SF-36v2 Health Survey, and a quality-of-life analog scale at baseline, week 2, and week 4.

MAIN OUTCOME MEASURE:
Questionnaire and survey scores, evaluated through intent-to-treat and per-protocol analyses.